Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1999-06-18
2001-12-04
Lee, John R. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S234000, C358S471000
Reexamination Certificate
active
06326607
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a calibrating apparatus and method, and more particularly to a calibration target in a scanner.
2. Description of the Prior Art
FIG. 1
shows the external features of a scanner wherein machine base
30
includes main component parts such as, light source, sensors, analog-to-digital converter, amplifier and I/O interface. The material of transparent glass
40
on housing
20
can be replaced by other transparent materials, such as acrylic resin. Picture for scanning is downward on transparent glass
40
, and lid
10
covers picture to scan where scanning direction is from A to A′.
FIG. 2
shows the inside structure of housing
20
in FIG.
1
. Picture for scanning is upward under transparent glass
40
. Because a dark-white calibration is necessary before scanning, a calibration target
60
is in the housing
20
of a scanner where the calibration target
60
in the front of transparent glass
40
is perpendicular to scanning direction.
The scanning direction is from A to A′, and scanning order is calibration target to picture in sequence.
The structure of calibration target is a white calibrating area and a dark calibrating area, as shown in FIG.
3
. The white calibrating area gives sensors white calibration and steady output, and also defines the brightness of photography. The border between white calibrating area and dark calibrating area is set up the reference of scanning origin, because distance between the border and scanning document can be determined. The dark calibrating area does not provide dark calibration. The scanning direction in calibration target is from white calibrating area
62
to dark calibrating area
64
.
The fabrication of calibration target is that prints a long black bar in white board and paste on the transparent glass after appropriately cutting. However, system will have higher tolerance after cutting and sticking. Moreover, the cutting process will make more scrap materials higher cost in materials.
SUMMARY OF THE INVENTION
The present invention provides a cross-sectional area for calibration target to substitute dark calibrating area. Because cross-sectional area is formed with housing, the white board dose not need to print black bar and cost is down. Moreover, steps of process and assembler tolerance are reduced.
In one embodiment, the cross-sectional area for calibration target is formed by using housing formation in which cross-sectional area can be one of the rib on housing or trench in design. The dark calibrating area is substituted by a cross-sectional area that generates a drop in elevation and creates a border between dark area and light. The actual output by this invention is equivalent to prior art.
REFERENCES:
patent: 5336976 (1994-08-01), Webb et al.
patent: 5895913 (1999-04-01), Christensen
Bacon & Thomas PLLC
Lee John R.
Pyo Kevin
Umax Data Systems Inc.
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